WAIS-III Digit Symbol-Incidental Learning base rates: findings for college student and patient samples

Frequencies for Pairing and Free Recall of the WAIS-III Digit Symbol-Incidental Learning procedure were determined separately for 104 college students and 73 patients with substance abuse disorders. Means for age and education were 22.2 yr. (SD=5.1) and 14.7 yr. (SD=1.0) and 46.0 yr. and 12.2 yr. (SD=9.4), respectively. Base rate tables indicated that for Pairing, 93% of students and 89% of patients paired the number 1 with the appropriate symbol. Conversely, only 43% of students correctly paired the number 3 with its associated symbol, while 30% of patients paired the number 4 with its appropriate symbol. When Free Recall was assessed, 98% of students remembered the first symbol, but only 61% recalled the third. The most frequently recalled symbol by patients was the ninth (97%) and the most infrequently recalled symbol was the fourth (50%). The present base rate tables may be helpful for detecting unusual recall frequencies on the Incidental Learning procedures.